Typically, in cargo aircraft, the payload is transported in pallets which are secured to the aircraft with a cargo restraint system. The restrain is usually achieved by means of two sets of latches which immobilize the pallet in three main directions of the aircraft. These latches are commonly devised to resist a rough treatment and to adapt to different kinds of load, and therefore have loose dimensional tolerances.
Document AU 2014331897 A1 describes a mechanically actuated cargo restraint system for a vehicle which includes a rotatable reel in a frame, two flexible tethers, and a mechanical device for the actuation thereof.
Document US 2015329206 A1 discloses an aircraft cargo handling system with a pair of load restraining rail assemblies, each of which has a shaft assembly running substantially parallel to the longitudinal axis of the aircraft, which enables the pallets to be locked in place sequentially by rotating the shaft assembly a predetermined angular rotation each time a pallet is loaded.
Document US 2015225083 A1 describes a cargo restraining assembly comprising two guidance and restraint bars running in parallel to each other, and at least one lateral bracket spanning between the two guidance and restraint bars and being fixedly connected to each of the two guidance and restraint bars. The lateral bracket includes a bracket foot formed integrally with the lateral bracket and a quick release mechanism configured to quick-releasably couple the bracket foot to a seat track profile of the cargo deck surface of the aircraft.
These inventions provide different ways of securing the cargo in an aircraft. But in some cases, when special equipment sensitive to shocks and vibrations is transported, or palletized seats are installed, the gaps between the cargo restraint system and the pallet must be reduced to zero in order to avoid unexpected movements and vibrations during flight.
Restraints with a nonexistent gap or a close to zero clearance can be used to overcome the rattling problem, but these kind of fixations usually require longer manipulation periods and the use of specialized tools, like screwdrivers, spanners or keys.
However, for certain applications, extended operation times are unacceptable, and therefore specific anti-rattling devices that can be easily fastened and/or released must be installed in the pallet. In addition, the restraint of the pallets in the aircraft cargo system must be done in all three main directions of the aircraft.